1. Field of the Invention
The present invention relates to a gas-sensitive semiconductor device. Moreover, the present invention relates to the use of such a device.
2. Description of Related Art
This type of device is generally known from the related art, and is described, for example, as a so-called CHEMFET in U.S. Pat. No. 4,411,741.
This technology, which is used to define the species and is presumed as the current related art, relates to gas-sensitive semiconductor components having a gas-sensitive layer whose electrical properties may be altered by absorption or adsorption of gas, and which have an effect on the electronic behavior of the semiconductor component, in particular a change in conductivity of the semiconductive channel, with the effect that, for example, as a response to an acting gas to be detected, the current flowing between the first channel electrode (drain, for example) and the second channel electrode (source) is altered.
In particular, in the related art use is made of the effect that an interaction of gas molecules, to be detected, with a gate electrode which is catalytically active, for example, causes a change in the effective applied gate potential which in the manner described brings about a signal change of a drain-source current as a typical (sensor) measuring signal or detection signal.
It is known from the related art to induce selectivity with respect to certain gases, i.e., to allow the described interactions which cause the change in conductivity only for certain gases or gas mixtures, by selecting or installing suitable gate electrode materials.
However, it is difficult to clearly and distinctly develop such selectivities with respect to a single gas species, which usually results in undesired influences (cross-sensitivities) due to additional gas components. In this regard, it is known from the related art to compensate for such superimposed (and undesired) signals generated in this manner, using electronic or computational means, it being common in particular to detect the various gas species with the aid of a detector field of a plurality of CHEMFETs (as a sensor array) having different sensitivities, in order to then ascertain the desired information from the individual sensor signals in downstream evaluation units, using computational means. Aside from the associated complexity of evaluation, complicated multiplexer technology and/or multiple electrical feed lines to each individual CHEMFET are/is necessary for the signal transmission.